Position tracking, transmitting, and recording



Dec. 31, 1946. -c. G. DUNN ETAL POSITION TRACKING, TRANSMITTING, ANDRECORDING Filed May 5, 1943 6 Sheets-Sheet 1 AAA III-l 40 Dec. 31, 1946.c. s. DUNN ETAL 2,413,300

v POSITION TRACKING, TRANSMITTING, AND RECORDING Filed May 5, 1945 6Sheets-Sheet 2 j? .73 2g {Z w Susavx c 5 Q '2 W Seas 5 22 INVENTORS (712mm BY Ff Ykllz'zzgfow m Dad. 31, 1946'. NN L 2,413,300

POSITION TRACKING, TRANSMITTING, AND RECORDING Filed May'5, 1943 6Sheets-Sheet 3 mmvrons (i (1'. flunh/ 17.1 fill/glow \"l 31, 1946. c. G.DUNN EIAL 2,413,300

POSITION TRACKING, TRANSMITTING, AND RECORDING ma May 5, 1943. sSheets-Sheet 4 INVENTORS C (7' flan" 3y KI gellir rgfon I 7' NEW 31,1946. Q DUNN ETAL 2,413,300

POSITION TRACKING, TRANSMITTING, AND RECORDING Filed May 5, 1945 6Sheets-Sheet 5 RICA INVENTORS 6 d flann BY 5. [Mg/0n J 1 l l Dec. 31,1946.

c. G. DUNN ETAL 2,413,300

POSITION TRACKING, TRANSMITTING, AND RECORDING Filed May 5, 1943 6Sheets-Sheet 6 Patented Dec. .31, 1946 POSITION TRACKING, TRANSMITTING,AND

V nsoonnmc chimes G. Dunn, Fort Leavenworth, Kans., and

Wentwor'th J. Tellingt on, West Point, N. Y.

Application May 5, 1943, Serial No. 485,700

The invention relates to new and useful means for automaticallyallocating positions of vehicles on terrain with respect to an orientedmap and 5 Claims. (Cl. 177-352) instantaneously and continuouslytransmitting coordinate positions thereof to a receiving or recordingmap station where said positions are automatically rendered visible toobservers.

Objects and advantages of the invention will be set forth in parthereinafter and in part will be obvious herefrom, or may be learned bypractice with the invention, the same being realized and attained bymeans of the instrumentalities and combinations pointed outvin theappended claims.

The invention consists in the novel parts, constructions, arrangements,combinations and improvements herein shown and described.

The accompanying drawings, referred to herein and constituting a parthereof, illustrate one embodiment of the invention, and together withthe description. serve to explain the principles of the invention.

f the drawings:

Fig. 1 is a schematic diagram of apparatus embodying the invention,showing the basic coordinate-determining mechanism and radiotransmission means therefor; 1

Fig. 2 is a perspective view of a course plotting mechanism operative inconjunction with the apparatus of Fig. 1;

Fig. 3 is an enlarged fragmentary detail of the cosine solving mechanismshown in Fig. 1;

Fig. 4 is a diagrammatic showing of the geometric solution of thehorizontal component of speed or travel mechanically performed by themechanism of Fig. 3; a

Fig. 5 is a vector diagram showing the resolution of the polarcoordinates of travel Fig. 6 is a view similar to a part of Fig. 1,showing a modified form of coordinate deriving apparatus for radiotransmission;

Fig. 7 is a schematic-diagram of a preferred form of receiving apparatusfor'radio-transmitted coordinates and plotting mechanism associatedtherewith;

Fig. 8 is a perspective view of a situation map and a plurality ofcoordinate projectors arranged to cooperate'therewith;

Fig. 9 is a fragmentary front end elevation of a coordinate projector;

Fig. 10 isa verticalsection on line III-l0 of Fig.

Fig. 11' is an enlarged fragmentary view in perspective of the plottingboard shown in Fig. 2, illustrating the transmission of observed items;

Fig. 12 is an enlarged fragmentary detail, in elevation, of thecoordinate indicating details shown in Fig. 1;

- Fig. 13 is a partly diagrammatic plan view of the base of theprojector shown in Fig. 10; Fig. 14 is a fragmentary diagrammatic detailof a modified means for transmitting one of the coordinates of vehiclemission; and

Fig. 15 is a similar view of apparatus for receiving and converting tomechanicalmotion the energy transmitted by the apparatus of Fig. 14.

The invention is directed to providing novel and useful means fortransmitting to a receiving observer, in accurate form, visualinformation of the location of objects such as vehicles, personnel andother items of military interest; to do so instantaneously and secretly;and to make such permanent records of the transmitted information as maybe desired. More concretely stated, the invention provides automaticmeans whereby the position of any moving vehicle (tank, scout car,airplane, .etc.) is automatically and continuously determined withrespect to th terrain over which it is passing and such determinationsinstantaneously, continuously and accurately transmitted to one or moreoriented receiving maps at headquarter stations. Thus, the positions andmovements of every friendly vehicle in a given zone or sector can beshown at all times on a centrally located situation map.

Using the same equipment the operator in any vehicle in the field canalso instantly throw onto the receiving map at headquarters the positionand identity of any observed matter of military interest. Thus anoperator in an observation plane or other vehicle or station can causeto appear on the map at headquarters the presence, position and identityof an enemy battery, body of troops or any other static or moving thingseen by the observer in the plane.

Coordinated with the same basic transmitting motion by radiotransequipment the invention provides, for each veto an automatic.

hicle using the same, aself-oriented record track of its position andcourse on a map or other reference means carried by the vehicle, thusenabling the driver always to know where he is and where he has been.This feature of the in- .vention is simple, rugged, foolproof and initself novel and superior features.

The invention also contemplates provision of equipment utilizingprinciples heretofore mentioned whereby a. course previously followed orlaid out over unmapped terrain can be used as guide for vehiclesretracing that anaeoo course. Thus vehicles can be directed over andheld to predetermined courses regardless of conditions of visibility orknowledge of the course to be followed.

The invention permits the use of exceedingly simple and provenmechanical andradio equipment and, very simple and elementary forms ofradio transmission may be used. Nevertheless, ranges of reception andtransmission are of substantial extent while interception andinterpretation of the transmitted data are difilcult so that danger oflocating the transmitting vehicle or station and interpretation of thetransmitted data are relatively slight.

Broadly described, the basic coordinate-determining and transmittingmechanism comprises a simple mechanical plotting and mapping machine anda special radio transmitter automatically coupled with the travelmovements of the vehicle. These devices are preferably combined in oneconvenient unit mounted in the body of a scout car, airplane or othervehicle. The plotting and mapping machine, working from the polarooordinates of the vehicles speed and direction,

resolves them into north-=south and east-west coordinates, saidcoordinates being applied in the form of mechanical motion to markcontinuously and automatically on a mapping board the course oithevehicle over the terrain on which it is located and which is shown onthe map. Said l-. -S and BMW coordinates are also transformed frommechanical motions into terms of varying radio frequencies and saidfrequencies transmitted to a distant receiver or receivers. The radioreceiver sac-converts the received frequencies into mechanical motionswhich are applied to record the course of the vehicle on an individualmapping board. The received and converted N'S and E-W coordinate motionsare also utilized to operate li ht projector which throws onto arelatively large situation map screen a beam of light symbolizing theposition of the transmitting vehicle, 5 the position of that vehiclechanges, the projector moves to throw its vehicle symbol to the changedpositions on the map, thus continuously and instantaneously presentingto the observer the map position of said vehicle at all times. Byproviding all vehicles (or selected vehicles) with such transmitters, aplurality of receiving projectors can illustrate on the same situationmap at the same time the posiwithin their range of observation orinformation.

For example, an observation plane or reconnaissance car can cause toappear on the situation map at headquarters the presence, position andidentity of any observed matter of military interest such as an enemybattery, body of troops or the like. This is done by transmittingthrough the same radio transmitting means the observed position of theitem in the form of its N-S and E-W coordinates, as same are seen or areunderstood to be from the position of the transmitting vehicle. Otherobserving vehicles may simultaneously transmit the same information andthereby provide intersecting data which will enable the observer atheadquarters to obtain an accurate idea of the position and movement ofsuch observed items.

It will be understood from the foregoing general description and thefollowing detail description as well are exemplary and explanatory butare not restrictive of the invention. Referring now in detail to presentpreferred embodiments of the invention, same are illustrated in theaccompanying drawings. The primary step of the invention depends uponthe resolution of polar coordinates of vehicle position and travel intoN-S and E-W coordinates, i. e., rectangular or Cartesian coordinatesapplicable to properly oriented maps of the terrain under observation.Said polar coordinates are (1) the true horizontal speed of the vehicleand (2) the true azimuth of the vehicles direction. Given these polarcoordinate elements (which in practice are obtained directly from thevehicle through its speed of travel and true-direction-deternuningmeans,

such as a gyro compass) the mathematical process whereby same areresolved into N-S and E-W coordinates is illustrated in Fig. 5. Asshown,

oA- horizontal speed of the vehicle, c2=th8 azimuth of its direction BA(00) represents its E-W coordinate CA (0B) represents its N-S coordinateThen:

(a) EAL-GA sine e (b) CA=OA cos c=Ga sine ('-e) for obtaining the truehorizontal speed of the vehicle is shown in Fig. l, where the disc illof a ball and disc drive is rotated by the speedometer cable ii of avehicle (not shown) in which the apparatus of Fig. l is carried. Thusdisc it rotates at a speed proportional to the actual or slope speed ofa vehicle traveling over the ground, whether some be level or inclined.A pendulum or plumb bob i2 is freely pivotally supported from thevehicle by means oi a shaft to pivoted about fixed pin it. Thus theshaft to and bob 8? function as a plumb line constantly establishing anangle equal to the fore-and-aft slope of the vehicle with respect totrue horizontal. Erratic movements of the shaft and bob are prevented bymeans or a damper or shock. absorber comprising the cylinder and pistonconstruction i5. Disc to frictionally drives horizontal speed cylinderas through standard dual ball drive tile The radial position of the ballcarriage 25 with respect to the disc it determines what proportion ofthe speed of the disc is transmitted to the cylinder so in accordancewith the known law of operation of such ball and disc drives. Inaccordance with this feature or the invention the radial positions ofthe ball carriage 2i are varied in accordance with the slope angle ofthe vehicle so that the cylinder to will always rotate proportionatelyto the true horizontal speed of the vehicle. Accordingly, ball carriage2i is mounted on horizontally disposed arm 22 which is moved in and outdistances varying with the cosine of the angle of slope. This factor isintroduced by means of the cosine-solving mechanism 23, the detailedconstruction and operation of which are shown in Fig. 3 and described hidetail below.

As shown, the pin l l on which arm 53 is pivotally mounted also supportsa T-shaped member having the stem portion to and the head portion it.The inclined bar 23 is pivotally connected through pin ii to a verticalslot in member it so that said pin it is constrained to slide in saidslot. At its other end bar 23 is similarly constrained by pin 2d toslide horizontally in a slot in the stem portion 45 of the T member. The

weighted bar I! is provided with an L-shaped extension I! pivotallyconnected by pin l9 to the center point of bar 28. Thus, as the am Itswings through ang e 3 due to the slope of the vehicle, the inclined barIt always takes up that same angle 3 with respect to the right-angledlegs II and it of the T member. Consequently, the quantity cos p isrepresented by the distances "-24. The horizontal arm 22 is alsopivotally connected to pin 24 and is constrained to slide parallel withthe stem member l5 by being sleeved therewithin. Thus the relationshipillustrated by the triangle in Fig. 4 is mechanically maintained andsolved by the mechanism shown in Fig. 3.

The true horizontal vehicle speed, represented as the rotation ofcylinder 20, is transmitted equally to two vertical shafts 30 and 3|,respectively, by beveled gears at the ends of the cylinder shaft 32,thereby to provide the polar coordinate of true horizontal speed for theresolution of each of the N45 and E-W coordinates, respectively.

of the vehicle direction, i. e..angle a) includes shaft 35 which isturned proportionately to said angle a. The measurementof said angle maybe and preferably is obtained from a gyro-compass diagrammaticallyindicated at 36, said compass having means for transmitting suitablemechanical motion to the shaft 35 in known manner. Such means may besimilar, for example, to those used in the directional gyro controls ofan automatic pilot, type -A-2, as shown and described, for example, inWar Department Technical Manual on Aircraft Instruments, 'I'M-1-413,dated February 2, 1942, pp. 150-161, used if desired in combination witha directional gyro indicator of the type shown in said training manual,pp. 132- 139.

Such directional indication and, turning of the shaft 35 may also beobtained instead from means operatively coupled to the steeringmechanism of the vehicle such as illustrated for example in U. S. Patent1,718,689 to Grafstriim, dated June 25, 1929. In said patent a lever isactuated by the steering mechanism, which lever positions the ballcarriage of a ball and discdrive proportionate to the amount of turning.The disc of this drive rotates proportionate to speed of the vehicle.The output rotates an amount equal to the product of the speed and angleof tuming, the resultant rotation always indicating the presentdirection of'the vehicle. As will be obvious, the patented device can beapplied in similar manner to rotate the shaft 35.

In accordance with the invention the E-W coordinate of the vehiclemotion is obtained by multiplying the horizontal vehicle speed (that ofshaft, 30) bythe sine of angle a, while the N-S coordinatev is similarlyobtained by multiplication two coordinates by ball and disc drives,wherein the product of the horizontal speed times sin a are obtainedthrough radial displacement of the ball carriage 31, over the face ofthe-horizontal speed disc 38, said-displacement varying with the sine ofangle a. The ball carriage drives a frictionally contacting horizontalcylinder 39, the rotation of which is therefore proportional to the E-Wcoordinate of the vehicle's motion.

Similarly, the ball carriage is displaced radially across the face ofhorizontal speed disc ll from a horizontal rack bar 19 for translationin the E-W in proportion to 1 through clutch 6|, shaft 62 the cosine ofa, thereby drive horizontal cylinder 42 proportionately to the N-Scoordinate of vehicle speed.

The displacements of the ball carriages 31 and ll in accordance with thesine and cosine of a, respectively, are effected by means of a 360 sinecam comprising the cylinder ll having suitable sine cam groove 40 alongthe cylinder surface thereof. Said cylinder is rotated in accordancewith the angle a by means of cylinder shaft 41 which is driven from thedirectional shaft SI. The cam follower 49 is adjustably and resilientlyconnected to the arm 49 of ball carriage 31 and is so adjusted on thecam with respect to disc 39 that it will occupy the center thereof, asshown, when the azimuth of the vehicle direction is 0 and when it is180. Thus in the position shown. the azimuth of the vehicle direction iszero, 1. e. true north, the ball carriage 31 is at the center of disc 39and hence no motion is transmitted to cylinder 39, there being no E-Wdirection. In similar manner cam follower is connected to ball carriage40, the follower being mounted in the cam groove displaced 90 from thefollower 49. Hence the movement of follower will correspond to thecosine of or and inthe position shown it is at the perimeter of the discand thus transmits the maximum value of unity to the drive of cylinder42 from disc 91. It will have the same radial displacement in theopposite direction at 270.

The equation for the-ball and discdrive- 31-49 is:

(cl w where Se=Speed of cylinder Sa=Speed of disc K=A constantD=Distance of ball carriage from center of disc Substituting in Equation0 Sd=OA=Speed of vehicle D=Sin a=Sin of azimuth Hence speed ofcylinder=E-W coordinate. From Equation 1) above:

. m=o sin (90 a) Thus the speed of cylinder 42 in ball and disc drive4H1 equals the N-S coordinate.

A shaft for transmitting the E-W coordinate motion of cylinder 39 isdrivingly connected and beveled gears 63 to the shaft of said cylinder39. Similarly shaft 95 transmits. the N-s coordinate motion by similarconnections to the shaft of cylinder 42.

In accordance with the invention means are provided for continuouslyrecording on a map the motion of the vehicle as derived from thecoordinate motions of the shafts 60 and 65 and such means are shown inFig. 2. As there shown a provided for carrying vehicle may be inscribedby a stylus H. Said stylus is adapted to be moved in the E-W directionby motion transmitted from shaft and in the N-S by motion transmittedfrom shaft 85. For this purpose the stylus is mounted on a. travelingarm 12 which is attached,to and projects which is adapted direction.Such to the rack by at either end of translatory motion is impartedmeans of spur gears 14 and 15 a map or sheet upon which the positions ofthe movingthe map board, said gears being driven directly from shafts 80as will be clear from the drawings. Hence any rotation of shaft 88 willcause translation of said rack and thereby move the stylus 12 incorresponding in the E-W direction across the map.

Means for imparting motion to the stylus in the N-S direction on the mapfrom the N-S coordinate shaft 65 comprises a grooved slide $6 in whichthe rack '13 is slidable. Said slide is mounted on trucks 8! and 82 atits ends, said trucks riding on trackwa'ys 83 and M, respectively.Motion in the NS direction is imparted to the slide 89 by means of apinion gear 35 at the end of shaft 65 meshing with rack 86.

Means are provided for continuously transmitting both the coordinates byradio in terms of audio frequency to a receiver at the vehicles base orheadquarters. That is, the motion corresponding to the E-W coordinate isconverted into an audio frequency proportional to said motion and theresulting frequency transmitted by suitable carrier wave to a receivingset. Thus variations in the transmitted frequency will be received asvariations in the E-W coordinate and similarly as to the N-S coordinateand the receiving recorder thereby will be accurately and continuouslyinformed as to the exact coordinate positions of the vehicle as sotransmitted.

One form of means for converting the coordinates into frequencies andtransmission of same by radio is shown in Fig. 1 wherein motion of theE-W coordinate shaft to is transmitted to a shaft 53h which transmitsits motion to a shaft i supporting the rotary armature 9 2 of aninductor motor. The field coil 93 of said motor is suitably energized bya D. C. circuit as.

Preferably the range of audio frequency assigned to the E-W coordinatewill be within a definite band markedly different from that for the N-Scoordinate. Accordingly, means are provided for adding a constant basicspeed to the variable coordinate speed introduced by shaft 9t so thatshaft at of the inductor motor will rotate at a speed which is that ofshaft 9t plus the added basic speed. For this purpose the shafts ti? andiii are connected through a differential 95 into the gearing of which isalso connected a constant speed motor 95 so that the speed of said motoris added to that of the shaft 9% and shaft 9i therefore rotates at aspeed representing the sum of the speed of shafts 9t and constant speedmotor. The aggregate speed so imparted. to the armature 2 is, by meansof the inductor motor, used to generate an equivalent frequency which isthen broadcast by means of the transmitter ltd. Said transmitter may beof any suitable type and design, a preferred form being that known as U.S. Army Signal Corps radio trans-' mitter (series 193). A suitablecircuit we may be provided for modulating the frequency between theinductor motor and the transmitter.

In similar manner the N-S coordinate from shaft 65 is converted to audiofrequency through inductor motor m5 and additive constant speed motorace and, by means of the same transmitter E63, broadcast concurrentlywith the E-W coordinate, it being understood that the frequency productof the inductor motor 585 is in a diiferent frequency range so that thetwo coordinates are in quite different frequency bands. Since thefrequency ranges required for the coordinates are not great, a channelmay be left open for the transmission of messages by continuousshortwave telegraph or telephone.

In a modified form of the invention, preferred for simplicity as well asaccuracy of transmission of coordinates by radio, meansare providedfortransmitting the N-S and E-W coordinates directly in terms of distances"from any pre-selected arbitrary base line-i. c. ordinate or abscissa.One great advantage of this modification is that the frequenciesreceived are in terms of absolute coordinate valuesso that it is notnecessary for the receiver to remain constantly tuned to thetransmittingstation in order to avoid the possibility of confusion due to a failureconstantly to receive the frequencies or to know their relation to andthe actual oriented positions on the map.

The modified mechanism for producing said transmission of distancecoordinates is shown in Fig. 6, wherein only the features of the apparatus which differ from those shown in Fig. l are illustrated. In thismodified system .a basic frequency, representing the minimum absolutevalue or arbitrary base N-S line from which the 'E- W coordinate is laidoff on the receiving map, is enerated by a constant speed motor Mil,which through suitable coupling drives the armature iEd of an inductorsimilar to that shown in Fig. 1. Means are provided for adding to thebasic coordinate frequency of motor drive its a frequency-generatingspeed corresponding to the distance of the E-W coordinate of the vehiclefrom that base. As shown, the E-W shaft Eii (driven from cylinder 39 aspreviously described, Fig. l) is connected to pinion shaft i l l fortransmitting motion to racl; M2, to the end of which is attached ballcarriage N3 of a ball and disc drive. The disc M l thereof isdirectlydriven by constant speed motor lit, while the driven cylinderlit rotates at a speed equal to or greater than that of the motor shaft,depending upon the radial distances of the ball carriage M3 from thecenter of disc i Hi. The shaft of cylinder 4 it is geared directly tothe shaft fit of the inductor motor armature iZt. Hence the base or zeroE-W coordinate will be produced as a frequency directly proportionate tothe base speed of motor lid when the ball carriage H3 is at the zeroposition of disc-lid. When any motion is imparted to shaft til, the ballcarriage will be moved away from the center of the discand thereby theinductor motor driven at a higher speed to generate a higher frequency.Thus the frequency generated by said motor will correspond directly orin absolute relationship to the E-W coordinate distance of the vehiclefrom the base or zero line on the map. It will be understood that thefrequency generated by the inductor motor will be transmitted by a radiotransmitter ltd with suitable carrier wave, as previously described. Itwill further be understood that the N-S coordinate, with a suitable basefrequency, will be generated and fed to the transmitter tilt in likemanner by similar apparatus, not shown.

Referring now to those features of the invention relating to thereception and recording of the radio-transmitted coordinates of the"vesicle, same are generally shown in Fig. A radio receiver I36 (whichmay be of standard U. S. Army Signal Corps type, series 193) is providedfor picking up the audio frequency generated and broadcast by either theapparatus as shown in Fig. 1 or as modified, Fig. 6.

In Fig. '7 there is shown apparatus for receiving and recordingfrequencies transmitted as previously described. Said apparatus of Fig,7 is adapted to utilize directly the audio frequency er I, is fed intothe vehicle, a copper-oxide galvanometer energy from the receiver forthat purpose or. as i an alternative, to receive said frequencies andtransmit them to the recording apparatus by the interposition ofmanually operated means. Referring first to the direct transmission ofaudio frequency energy, the frequency of the E-W coordinate, forexample, is separated from the carrier wave by circuit I40 and, throughtransformr a servo-motor device I42. The latter, which may be of anyknown form for converting and amplifying the energ of a received audiofrequency, such as hereinafter described (Figs. 1c and 15), is adaptedto convert said E-W coordinate frequency into mechanical mo-= tion atthe shaft I43, said motion being directly proportionate to that of thecoordinate frequency received. The motion of shaft I43 is transmittedvia shafts I and I45 to spur gear I40 of a recording apparatusconstructed and operating essentially the same as that shown in Fig. 2;As shown, the spur gear operates a rack M1 which transmits East-Westmotion to a stylus I it as will be clear from the preceding disclosures.

Similarly the N-S audio frequency coordinate will be received byreceiver I00,'converted to me chanical motion by a servo-apparatus andsaid motion transmitted to pinion shaft I50 which,

through rack I5I, imparts north-south motion to the stylus carriage I52.

will trace on its map board as that drawn by the stylus which coursewill be that hicle with respect to the two identical maps,

which are equally arranged with relation to their respective plottingmechanisms.

In some cases it may be desirable for mechanical simplicity or otherreasons to avoid the use of a servo-mechanism in the receivingapparatus. Accordingly, the invention provides an alternative method ofconverting the received E-W and NS audio frequencies into the requiredmechanical motion by the interposition of manual receiving and operatingmeans. Referring to Fig. '7 a fader device, comprising resistance I 55,is designed to receive the transmitted audio frequency of the E-Wcoordinate after same has been cleared of the carrier wave by circuitI40 (inductance I56 being provided for this purpose). A switch I51 isarranged to cut out the servo motor circuit and cut in the fader circuitwhen the former is not-to be used.

Resistance I60 of the fader is arranged to car- 1'3; 9. frequencymatching that of the frequency received in resistance I55. Thefrequencies on resistances I55 and I60 of the fader are balanced forsignal volume'by operation of the knob of shaft I 68 in known manner,these frequencies being heard as two tones in the earphones of head setI62. When the frequencies on resistance I60 matches that on I55, thematching will be indicated very accurately as the two tones then becomea beat. To assist the operator in indicating sudden changes of directionon the part of I63 may be placed in parallel with the head set, thethrow of the needle thereof indicating the direction of change.

Means are provided for generating very accurately the matching frequencyon resistance I 50 and simultaneously for providing energy proportionalthereto which may be used to'operate the stylus-moving mechanism of themapping recorder. For this purpose an inductor motor I is connected tofader resistance I00 through a refining circuit "I, the armature shaftI12 of Thus the stylus I48 I53 the same course TI on map board 10,followed by the ve- Mi (an m ported by frame 20d.

53 ently throw its beam of to move over the map 10 the motor beingdriven at the speed required to provide the matching frequencies. Thedrive of said motor shaft is mechanically similar to that shown in Fig.6, comprising driven cylinder I15 01' the ball and disc drive mechanismwhich derives its basic speed from constant speed motor I16. The ballcarriage I11 of said driye is positionally controlled by the manualoperation of shaft I16 which, through differential I19, operates therack and pinion N30 to vary the position of the ball carriage. Means forproviding an accurately controlled rate of change in the movement of theball carriage, and thereby in the changes of fre-- quency set up inresistance M30, comprise means for applying motion through differentialI19 by th variable speed ball and disc drive linking cylinder I it, discM6 and constant speed motor I 81, he position of the ball carriage tiltis regulated by the rack and pinion I89 controlled by manual-.

iy operated shaft I90. It will be understood that the operator listeningthrough head set I62 will turn shafts H8 and I90 until the frequency onresistance B60 matches that on I55.

As previously stated means are provided for transmitting mechanicalmotion corresponding to the frequency on resistance I60 to the drivingmechanism of the mapping board. As shown, said means comprise theinterconnection of shaft extension of the pinion shaft operating rack I)with the drive shaft I45 of the mapping board by means of differentialI92. Thereby a mechanical motion corresponding to the matching frequencyis directly generated and transmitted to the spur gear I 40 of themapping mechanism.

Similarly it will be understood that mechanically identical means willbe provided for matching and transmitting the mechanical equivalent ofthe matched frequency of the N-S coordinate to the shaft I 50 of themapping mechanism.

Further, in accordance with the invention, means are provided forprojecting onto a large situation map or the like the position of themoving vehicle as indicated by a beam of light, which beam is positionedand controlled in accordance with the received and resolved coordinatesof the vehicle travel. Referring to Figs. 8, 9 and 10, the lines of alarge situation map 200 are printed or otherwise depicted on a,translucent screen sup- A plurality of light projectors 205, eachcorresponding to one of the vehicles to be shown on the map, are mountedin suitable relation with each other on a supporting rack 206 so thateach of said projectors can independlight on to the back of thetranslucent map screen. By means described below the beam from eachprojector is caused in conformity with the movement of the transmittingvehicle. Preferably each vehicle will be identified by providing in theprojector beam a mask outlining a suitable identifying silhouette orsymbol corresponding to that individual vehicle. Hence persons observingthe map on a, screen will see depicted thereon not only the terrain on'which the vehicles are located, but will see at all times the actualpresent position and movement of each of said vehicles. The previouscourse of each vehicle may be quickly obtained by referring to theindividual aaraaoo cal axes much in the manner of the telescope or beremovably mounted in the gate of the projector a transit. In order toproject on to the flat map screen 200 a motion equal to thecorresponding N-S coordinate movement of the vehicle, it is necessary torotate the projector through an angle whose tangent is the N-Scoordinate. \Accordingly, means are provided for so moving the projectorangularly in the vertical plane. For this purpose a flexible shaft M isrotatively driven with the same angular movement as that of the N-Scoordinate shaft I50, previously described in connection with Fig. '7.Said shaft H0 is connected to drive a worm gear 2 which lies beneath andparallel to the axis of the projector barrel 2|2. Said barrel issupported in a collar bracket 2l3 having a vertically bored projection 2through which the upwardly extending arm 2l5 is constrained to slide. Atthe opposite side of said collar 2l3 there projects a supportingtrunnion 22l which is rotatively mounted near the upper end oftriangular bracket 225, whereby the barrel 2 I 2 may rock in thevertical plane. The

lower portion of said arm 2 I 5 is offset horizontally at 2l6 and againvertically at 2!! to underlie the axis of the projector barrel 2l2. Atits lower end arm 2" is pivotally connected by horizontal pin 218 to theupstanding yoke 2 IQ of a threaded sleeve 220 adapted to engage andtravel along the worm gear 2| I. Thus it will be evident that motion ofthe worm gear in either direction will cause the sleeve 220 to betranslated and thereby to tilt the barrel of the projector through anangle whose tangent is that of the horizontal movement of the sleeve220, Le, the N-S coordinate. Consequently, the image projected on thescreen by the projector will move through a projected distanceequivalent to that of the N-S coordinate and, by proper positionrelationship between the projector and the screen the scale of suchmovement will be that of the particular map used.

In like manner horizontal rotational motion is imparted to the projectorabout its vertical axis. For this purpose the supporting bracket 225 ofthe projector barrel is based on a rotatable turntable 226 which isrotatively received within an outer stationary cylindrical receptacle221. The turntable 226 is ban-shaped and provided with upstandingbracket portions 228 and 229 for rotational bearing of the ends of theworm gear 2| I. Rotational motion is imparted to said turntable 226 byworm gear 280 (Fig. 13) driven by a flexible shaft 245 connected to thedrive of shaft N5 of the E-W coordinate.

A threaded sleeve 242 is mounted about .the

worm gear 240 and arm 2E3 is pivotally connected to said sleeve by yokeand pivot pin construction 2%. The axis of the worm gear 240 is parallelto that of worm gear 2 I! and is supported from the rim of receptacle227 by parallel arms 246 which are joumaled at their ends to rotatablysupport the worm gear. The arm 2&3 is constrained to slide through asleeve 245 which is fixed to the turntable 225 so that when the sleeve282 is at the center of the worm gear 240, the arm 243 extends normal tothe axis of the worm gear and,

over the center point of the turntable, which point underlies thecentral longitudinal axis and the central vertical axis of the projectorbarrel. Hence the horizontal motion of the projector will be that ofangles whose tangents are those of the imparted E-W coordinate.

The internal construction of the projector may be of any suitable designand as conventionally shown comprises -a lamp 230 before a, reflector23l and having focusing lens 232. A mask 234 m y the observation ofthose seeing the map. Angular movements of the projector 205 willnormally be suflicient to cover the movements of that vehicle within thelimits of the map. However, .to avoid too great a degree of angularitybetween the proje'ctor and the plane of the map, any projector may bemoved to a better location on its supportins rack 200 whenever thatbecomes desirable and suitable orientation thereof with respect to themap can be established for further operation.

In accordance with the invention same also, includes means fortransmitting and visually presenting the oriented map-coordinatedpositions of any observed items of interest which may be seen from thetransmitting vehicle. In general, the

same basic mechanism hereinbefore shown and described will be utilizedfor this additional function of the invention. In carrying out thisfeature of the invention, reference may be had to Fig. 11 wherein isshown a map of African terrain, said map being oriented and set into themap board recording apparatus of Fig. 2. 0perating in the mannerpreviously described, the course of a vehicle which has traveled on theterrain depicted by the map beginning atwthe marginal point 250(corresponding to the E-W base coordinate) is shown by the black linesupon the map to have traveled over the roads toward the town of Beja toa point 25L Thereupon let us assume that the operator of the vehiclenotes an item of interest on the ground located at point 252 on the map,and desires to transmit intermation' as to the location and identify ofsuch item to his receiving headquarters. By means hereinafter describedthe operator may do so by manually moving the stylus of hisrecordingboard to point 252 on his map and thereby, through the transmittingmechanism hereinbefore described, in effect draw a straight line or rayover the map from point 25l to point 252 and there mark-suitable indiclawith the stylus. This free movement of the stylus across the map willresult in the transmission of rapidly changing coordinates to thereceiving set and thereby effect the drawing on the receiving set of theline or ray as stated. Having so indicated the coordinate position ofthe item at point 252, the operator restores the stylus to the presentlocation of his vehicle on the map and operation continues in the normalway. Similarly the location of item 252 may be indicated by the operatorwhen his vehicle has reached another point such as 253, therebyestablishing intersecting rays on the recording maps and so locating thepointer item with greater accuracy. Obviously the same item disengagedand the stylus on 13 shape or symbol at the point indicated by means orthe stylus or same may be done by transmission of a verbal descriptionover an available channel in the radio transmitter.

Referring now to the embodied means for effecting the above describedoperations, it will be seen that manually operable clutches 6| areprovided for the shafts 60 and 65 of the basic coordinate mechanism,such clutches being operable either with the constructions shown in Fig.1 or that of Fig. 6, as will be apparent. When it is desired to performthe operation depicted in Fig. 11, the operator at the vehicle mappingboard will declutch both coordinate shafts by means of the two clutches6i and thereupon move the stylus 1| over the mapping board from thepoint 2; to the point 252 as previously described. This manual movementof the stylus will automatically rotate the shafts 6t and 6d and therebytransmit the coordinate frequencies evolved bysuch movement or thestylus through the transmitter M0 to the receiving stations.Consequently the movement of the stylus and coordinates of each point towhich it moves will be automatically transmitted by the same mechanismhereinbefore described. The stylus is then manually returned to thepoint or origin (if the vehicle has stopped moving in the meantime) orto the present point of the vehicle on the map if same has continued tomove during the manual operation of the stylus.

In the latter event, means are provided for facilitating return of thestylus to the present position of the vehicle with relation to the map.Such means comprise registering dials shown in Fig. 1 and in greaterdetail in Fig. 12, those for the E-W coordinates only being shown. Aswill appear from Fig. 12 a counter 260 is driven by shaft 26| which iscoupled to the shaft being driven by E-W component cylinder, 39. Thiscounter may appropriately represent the number of tens of thousands ofmeters on a map of the scale shown in Fig. 11. A ring dial 262 isprovided for recording the numbers of thousands of meters beyond the tenthousand presently indicated by counter 260, while ring dial 263registers the number of hundreds of meters, all three of these countingregisters being driven from the shaft 26E. Thus the E-W position of themoving vehicle is always indicated by the dials 262 and 263 regardlessof the position For example, the E-W coordinate of the vehicle at point253 is 1788.80 as shown by the dials and as will be apparent from themap, and said dials will continue to record and indicate the changingposition or the vehicle even not moving to trace the course of thevehicle.

A ten thousand registering counter 26%, thousands dial 266 and hundredsdial 261! are similarly connected to be driven by shaft 268 which isgeared to shaft 60. Accordingly, motion transmitted to shaft 60 by thedeclutched or manual movement of the stylus, will be indicated andrecorded on said register 26526l. During normal operation when thestylus is coupled to the vehicle-driven'shaft, the clutches 6| areengaged and the inner and outer dials are matched. After the stylus hasbeen used to plot a point other than the position of the vehicle, itmust be returned to the present position of the vehicle on the map. Thisis done by approximately matching the dails and reengaging the clutches.Each clutch is preferably toothed in such a manner that approximatematching of the dials, followed by engagement of the clutch, results inexact of the clutch 6|.

while clutch 6| is the map record is matching of the dials. Thus theoperator may disengage the stylus and indicate positions of otherobserved items at will but by means of the dials described above canalways return the stylus to the exact present position of the vehicle onthe map and automatic recording will continue as before. The samearrangement will, of course, be applied to the actuation of the similardevice for the N-S coordinates, it not being necessary specifically todescribe same. It will further be observed that the motions of thestylus will be recorded on the receiving map recorders just as they takeplace at the transmitting apparatus.

In Fig. 14 is shown an embodiment of mechanism for transmitting a formof wave energy which can be readily converted into mechanical energy atthe receiving station and, in Fig. 15,

means for so converting same. The mechanism in Fig. 14 is in part amodification of the transmitting means shown in Fig. 1, and that in Fig.15 in part a modification of the receiving apparatus shown in Fig. '7.

Referring first to Fig. 14, the shaft 300 is driven, like the shaft 60of Fig. 1, corresponding to the E-W motion of the vehicle and for thepurpose of this disclosure the motion of shaft 300 may be considered thesame as that-of the shaft this feature of the invention, is convertedinto electrical impulses, the number of said varying directly with theR. P. M. of the shaft. For this purpose shaft 300 is geared directly todrive shaft 30| of a sprocket or toothed wheel 302, the teeth 303 ofwhich are positioned to engage the tapered end of a pivoted interponent304, the opposite end of which is fixed to a cross bar 305. Said crossbar is mounted to rock on As will be clear from the drawings,

the pin 306. rotation of wheel 302 in the clockwise direction will causea tilting of the bar 305 in the opposite direction while reverserotation of wheel 302 will tilt the bar in the clockwise direction, andthere will-be such tilting and return of the bar each time that theinterponent 304 encounters one tooth of the wheel 302.

By this means the bar 305 is adapted to act as a switch for closing acircuit each time the wheel is rotated through the are between twoteeth. Thus the circuit comprising the wires 310 and 3 is closed eachtime that the wheel 302 rotates through the interval between two teethin the, counter-clockwise direction, while the cirtime the wheel rotatesthrough a similar interval in the opposite direction.

It will be clear that by this simple means electrical impulses will beimparted to the transmitter mechanism I00 at a rate corresponding to therotation of the shaft 300 and in a sense corresponding. .to thedirection of that rotation. Hence if the vehicle is travelling at say 30M. P. H. in the direction W to E a corresponding number of impulses willbe communicated through suitable connections, not shown, to thetransmitter I00 and will thereby be broadcast in known manner. If thevehicle is travelling at a similar rate in the E to W direction, thetransmitter will send out an equal number of impulses in the oppositesense. In this connection the transmitter will be equipped so as toprovide a definite band-of audio frequency for the impulses generated incircuit 3|03|| and a quite separate band forthe impulses of circuit 3|l3|2 (thus impulses 15 maintaining separate the two senses of directionfor the E-W component).

Referring now to Fig. 15, apparatus is shown for receiving the impulsestransmitted from the vehicle-connected transmitter I and for convertingsame into equivalent mechanical motion for operating a component shaftsuch as I shown in Fig. 7. In other words, the apparatus shown in Fig.is one form of means for converting the frequencies or impulses receivedby the radio receiver I30 into mechanical motion, which function hasalready been ascribed to the apparatus marked I42 in Fig. I. Saidapparatus I42 and the other means between same and receiver I30 may beconsidered as a diagrammatic showing of operative apparatus, oneembodiment of which is shown in Fig. 15 and described below.

For the purpose of cooperating with the impulse transmitter I00 of Fig.14, the receiver I30 is provided with two separate filtering circuitsgenerally marked 330 and 350, these circuits being respectively designedto receive the impulses corresponding to the W-E transmitter circuit3I0- 3| I and the E-W circuit 3I I3I2. The impulses so received by thefiltering circuit 330 are amplifled by suitable means 335 and thecurrent so produced is transmitted to the magnet plate 336. In the fieldof said magnet plate is positioned an armature 331, one end of which ispivotally supported on a shaft or pin 338. The armature 331 is formed asa right angle, and on the depending arm 339 thereof is fashioned a pawlor dog 0. Said pawl is adapted to engage a ratchet wheel 3, the shaft ofwhich is suitably coupled to drive a shaft 342 which, through suitabledifferential gearing 343, transmits its motion to the coordinate shaft Iin the apparatus of Fig. 7. Similarly the impulses of the opposite senseof the same coordinate are passed through the filter 350, amplifier 355and like motion-creating and transmitting means 351, 30I and shaft 362to the other side of the differential 343, whereby motion in theopposite sense may-similarly be imparted to the coordinate shaft I.

It will be understood that the apparatus shown in Figs. 14 and 15 isadapted for the transmission of say the E-W coordinate of vehicle motionin either directional sense and that similar apparatus (not shown) willsuitably be coupled to the transmitter I00 and the receiver I30respectively for the transmission and reception of both senses of motionof the vehicle in the N-S directions.

Many of the uses of the invention for military and like purposes will beobvious from the foregoing. Another use of particular value and interestis its applicability to aircraft warning service and anti-aircraftinformation service, with resultant elimination and simplification ofmuch work now done therein. Utilizing essentially the mechanism shown inFig. 11 with necessary related transmitting equipment, an aircraftwarning observer will manually indicate the course of an observed planeon his map board with the stylus, thereby transmitting the observedposition and course of said plane to the receiving station at the aircontrol center. The observer also, by pressing one or two of severalbutton switches (not shown), may transmit the number, type'and altitudeof the observed planes. Receiving equipment similar to that shown inFigs. '7 and 8 may be located at the air control center where theprojector 205 may be used to indicate on the large control map thecourse of approach- 1 ing planes. A supervising operator may switch outthe lights on those projectors which are least likely to be givingaccurate reports for a given location or direction of aircraft approach,thereby preventing confusion from too many projectors pointing out thesame plane. This use of the invention is of great importance ineliminating confusion and labor in aircraft warning service, especiallyas the reports can come direct from observers to the central boardwithout use of filter or similar time consuming operations.

The invention initsbroader aspects is not limited to the specificmechanisms shown and described but departures may be made therefromwithin the scope of the accompanying claims without departing from theprinciples of the invention and without sacrificing its chiefadvantages.

What we claim is:

1. A position recorder for vehicles including in combination a vehicle,means connected therewith for resolving the polar coordinates of vehicletravel into motion corresponding to the rectilinear coordinates of saidtravel, means for transmitting said rectilinear coordinates to a distantreceiving station, means for disconnecting said coordinate resolvingmeans from the vehicle travel motion, selectively operable manuallyactuated means for describing coordinates of positions apart from thatof the vehicle and connections for transmitting said latter namedcoordinates through said transmitting means to said distant station.

2. A position recorder for vehicles including in combination a vehicle,means connected therewith for resolving the polar coordinates of vehicletravel into motion corresponding to the rectilinear coordinates of saidtravel, means operated by said motion for converting same intoquantities capable of radio transmission, means for transmitting saidrectilinear coordinates toa distant receiving station, means fordisconnecting said coordinate resolving means from the vehicle travelmotion, selectively operable manually actuated means for describingcoordinates of positions apart from that of the vehicle and connectionsfor transmitting said latter named coordinates through said transmittingmeans to said distant station.

3. A position-indicating device including in combination a vehicle,means connected therewith for resolving the polar coordinates of vehicletravel into motion corresponding to the rectilinear coordinates of saidtravel, means for applying said rectilinear coordinates of motion to .astylus, said stylus being movable in oriented relation to a map, meansfor transmitting by radio the east-west and north-south rectilinearcoordinates of motion of the stylus with respect to the map, and manualmeans for moving said stylus to selected positions on the map while saidcoordinates are being transmitted, a similar map and stylus at areceiving station and radio controlled means for moving said secondstylus in conformity with the received coordinates of motion of thefirst stylus.

4. A device of the class described including in combination a vehiclehaving means for resolving motion of its travel into motionscorresponding to its east-west and north-south component directions withrespect to an oriented map, means for transmitting energy by radiocorresponding to each of said components and means cooperat- 17 natecomponents of positions remote from the vehicle.

5. A device of the class described including in combination a vehiclehaving means for resolving motion of its travel into motionscorresponding to its east-west and north-south component directions withrespect to an oriented map, means for transmitting energy by raidocorresponding to each of said components and means cooperating with theforegoing4or-simiiar1y transmitting through said transmitting means themapcoordinate components of positions remote from the vehicle, andreceiving means for automatically visually indicating on a receiving mappositions and indicia corresponding to those transmitted.

CHARLES GI DUNN.

J. TELIINGTON.

